Rat Population: 5 US States With the Most Rats

A female rat snuggling with her many babies against a white background
© Maryia Karneyenka/Shutterstock.com

Written by Jennifer Gaeng

Updated: June 6, 2023

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Rats are a diverse group of medium-sized rodents with long tails. There are rat species all over the Rodentia order, but the ones most people picture live in the genus Rattus. Neotoma, Bandicota, and Dipodomys are also rat genera. Size is the most obvious identifying feature of rats compared to mice. Since rats are such adaptable rodents, they have spread around the planet and can now be found almost everywhere except for the most inhospitable places, like Antarctica.

Over 60 rat species exist, and there are probably seven billion of them in the world. Nearly one rat for every human being. If you can believe it, rats are one of the few rodents that genuinely contribute to the natural world. They eat whatever is available, which makes them scavengers. They’ll consume anything people toss away, including trash. In addition, rats play a vital role in the predatory food web. Some snakes, lizards, and other reptiles specialize in eating rats and other rodents.

When rat populations get too large, they create a nuisance in urban centers. A small population of rats has the potential to rapidly multiply and become a major problem. This article will take a look at the states and cities with the highest rat populations in the United States. How did these areas come to be the home of so many rats? Which rat species does that area favor? Let’s find out!

Which States Have the Most Rats?

Black Rat

All rats are known to be disease carriers and have caused significant loss of lives in the past when hygiene in cities was not at a premium.

©Ernie Cooper/Shutterstock.com

Some even refer to Chicago as the “rat capital” of the United States. The title of “rat capital of the United States” went to Chicago for the ninth year in a row. Orkin claimed that the outdoor eating areas made popular during the epidemic were a perfect place for rodents to dine, live, and multiply.

Top 5 Rat-Infested Cities and States in the US

Two brown rats peeking out from a hiding place

Rats can infest a populated area quite fast since they love to eat garbage and there is a lot in the U.S.


Illinois, USA; Chicago

Chicago at dawn. Cityscape image of Chicago downtown at sunrise.

Because Chicago is known as a garbage dump, rats have made it their home.

©Rudy Balasko/Shutterstock.com

Rats have made Chicago their home because of the city’s reputation as a rubbish dump. Rats can find safety in the city’s many structures and feed on the mountains of garbage. Chicago’s predominant species is the brown rat.

The black rat, once widespread, has been pushed out of the east coast by this species’ dominance. Brown rats are highly proficient at swimming and climbing, making them much tougher to exterminate. Brown rats are burrow-dwellers that can have anywhere from six to twelve offspring every year. Females start reproducing after 2-3 months or less.

New York, USA; New York

A welcome sign at the New York state line.

New York City’s high population density is a major contributor to the city’s persistent rat problem.


Rat infestations remain a major problem in New York City, largely because of the city’s high human density. In this area, the brown rat predominates. Pathogens such as Salmonella, E. coli, and Leptospira are carried by rats in New York City. One major cause of New York City’s rat infestation is the city’s notoriously poor waste management. Although rats are typically nocturnal, many New Yorkers have reported seeing them during the day in parks, playgrounds, subway stations, and other public places.

California, USA; Los Angeles

As Los Angeles’s population has risen, so have the city’s overcrowding and homelessness, both of which have contributed to the city’s filthy circumstances.

©John Dvorak/Shutterstock.com

Overcrowding and homelessness have contributed to Los Angeles‘s unclean conditions as the city’s population has grown. Parts of the city are undergoing an epidemic due to the brown rat (also known as the Norway Rat), which is spreading typhus. People’s inappropriate disposal of trash and food is a major factor. Rat infestations are a problem not just in low-income areas. Even the most affluent neighborhoods in the city have a persistent rat issue.

District of Columbia, USA; Washington

Despite significant efforts to control the rat population in the nation’s capital, rodent complaints have hit an all-time high.

©Orhan Cam/Shutterstock.com

Complaints about rodents in the nation’s capital have reached an all-time high despite extensive attempts to reduce the city’s rat population. Dry ice, solar-powered garbage cans, and other solutions have all been tested by the city thus far with no success. The number of rodents keeps increasing. The dense population in some areas is a factor, as is the case in many other cities.

The number of rat sightings and complaints from residents on Capitol Hill is considerable. The number of eating establishments has increased by at least 25 percent over the past decade, leading to an increase in food waste and poor waste management.

California, USA; San Francisco

Aerial view of San Francisco Bay

San Francisco is experiencing an epidemic of rat infestations, and pest control agencies are overwhelmed.

©Engel Ching/Shutterstock.com

California hits this list for a second time, and it’s no surprise given how large and populated the state is. Rat infestations are becoming increasingly common in San Francisco, and pest control services are struggling to keep up. There is such a high need for exterminators that many of them have waiting lists. Both brown rats and roof rats can be found in urban areas.

While brown rats frequently burrow or make their homes in sewers, roof rats prefer to stay high and dry. In most cities, rodent infestations can be traced back to one thing: trash that has been left out in the open. Construction-related vibrations have been linked to broken subsurface pipes, which have in turn been linked to rat infestations. Rats have been known to enter homes through vents, pipes, and even toilets.

Summary of 5 US States With the Most Rats

Rank StateCity
2New YorkNew York
3CaliforniaLos Angeles
4District of ColumbiaWashington
5CaliforniaSan Francisco

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About the Author

Jennifer Gaeng is a writer at A-Z-Animals focused on animals, lakes, and fishing. With over 15 years of collective experience in writing and researching, Jennifer has honed her skills in various niches, including nature, animals, family care, and self-care. Hailing from Missouri, Jennifer finds inspiration in spending quality time with her loved ones. Her creative spirit extends beyond her writing endeavors, as she finds joy in the art of drawing and immersing herself in the beauty of nature.

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